Crane hook suspensions



March 3, 1964 A. J. R. BELFORD 3,123,340

CRANE HOOK SUSPENSIONS Filed 19 1 2 Sheets-Sheet 1 A t'terneys March 3, 1964 A. J. R. BELFORD 3,123,340

CRANE HOOK SUSPENSIONS Filed May 5, 1961 2 Sheets-Sheet 2 Inventor AdamJ, 4. fies/ford B Y Maw 222, rm

A tto'rney United States Patent 3,123,340 (IRANE HGUK SUEPENSIGNS Adam J. R. Belford, Corby, Northants, England, asslgnor to Stewarts and Lloyds Limited, Glasgow, Scotland Filed May 3, i961, Ser. No. 167,431 Claims priority, application Great Britain .luly 29, 1960 2 Claims. (Cl. 254-139) This invention relates to cranes, particularly gantry cranes and so called goliath cranes, having a load-lifting hook, a winding drum and a pulley-guided rope or ropes suspending the hook from the drum.

Normally the horizontal displacement of the hook suspensions, as in long or cross travelling, imparts to the hook a pendular action rendering the accurate picking up or depositing of the load a relatively diilicult matter, especially so in a crane with a high travelling speed and rapid acceleration.

In order to overcome this diiliculty various forms of crane hook suspensions are known each comprising an assemblage of ropes (or equivalent) converging to meet at the hook attachment and diverging upwards to a system of pulleys or guides in the crab of the crane, these ropes acting in the manner of the guy ropes to a mast but inverted and constraining the load to follow accurately the travel of the ane because any deviation or swing must cause slackness in one or more of the hoist ropes.

As distinct from these known crane hook suspensions the present invention provides an arrangement which includes means enabling linear swing, i.e., pendular motion in a vertical plane, of the hook in at least one direction to be inhibited or permitted at will.

A further feature of the invention resides in providing means as aforesaid which enables swing of the hook in two and therefore in all directions to be inhibited or permitted at will.

An advantage of the invention is that when locating the hook below an obstruction, the hook can be left free to swing to facilitate such location, but its swing as aforesaid can be prevented during travel of the hook suspension or of the crane.

The means of the invention may be fitted to the hook attachment or incorporated in the crab assembly of the crane, and it may be arranged to be operated or controlled by hand or by power, e.g. electrically or hydraulically or pneumatically.

From the foregoing it will be apparent that the invention can be carried out in various forms some of which by way of example will now be described with the aid of the accompanying diagrammatic drawings, whereon:

FIG. 1 illustrates a known way of preventing linear swing of a crane hook yoke in one direction in a vertical plane about the pulleys g, g;

FIG. 2 shows an embodiment of the present invention likewise for preventing linear swing in one direction but enabling the crane hook to be made free swinging when desired;

FIG. 3 shows an embodiment of the invention alternative to that of FIG. 2;

FIG. 4 shows another alternative embodiment;

FIG. 5 shows a developed form of FIG. 2 adapted to inhibit linear crane hook swing in one or other or both of two different directions or to allow the hook complete freedom to swing;

FIG. 6 shows an alternative arrangement to FIG. 5; and

FIG. 7 shows an hydraulic means within the scope of the invention.

It will be appreciated that at least three inclined ropes (or equivalent) are necessary to prevent linear swing of the crane hook in any direction; in the case of two ropes, as in the so called bifilar pendulum, linear swing can be 3,1233% Patented Mar. 3, 1964 prevented in one direction only, but by utilizing a second similar apparatus at to the first linear swing can be prevented in any direction.

In the known arrangement, FIG. 1, linear swing of a yoke parallel to the path AA is prevented in that the ropes b, I: passed about pulleys g, g to the winding drum are attached at different loci to the triangular yoke a of the crane hook d.

FIG. 2 indicates a means in accordance with the present invention whereby the rigidity of the hook at and bracket c in the direction AA may be released. Here the hook d is carried by a bracket c suspended from the yoke a by a hinge pin and a removable pin 2 is utilised to lock the bracket 0 and yoke a, removal of the pin enabling relative rotation of these members about the hinge pin f. It will be readily seen that with the pin e removed the suspension behaves in a similar fashion to that of FIG. 1, and by suitable choice of dimensions the locus of the hook centre can be constrained to lie almost on the same vertical centre line even when the locked yoke assembly a is canted. With the pin e removed, no obstacle to swinging of the hook remains. Within a limited are determined by the dimensions of the yoke the hook is free to swing while the yoke a rotates about pivot f to allow for the unequal displacement of f from the pulleys g.

The mechanism as shown in FIG. 2 consisting of the pulleys g, g, ropes b, b and yoke a determines the familiar 4 bar chain capable of limited relative displacement. With the pulleys q, q, fixed, displacement of a to the left results in an anticlockwise rotation of a and displacement to the right results in a clockwise rotation of a. The hook bracket 0 is pivotably connected to a by pivot f and may be rigidly locked by pin e. In the rigidly locked position, let a be displaced to the left. This results in an anticlockwise angular displacement of a and therefore of the bracket 0. Hence the hook at is displaced to the right with regard to yoke a. If the length from 7" to the hook center be correctly determined with regard to the length between the rope connection on yoke a then the left hand and right hand displacement will be equal (and opposite) and the hook center will experience no displacement in direction AA.

It the pin 2 be removed, the angular displacement of a is not passed on to bracket 0 so that linear swing is po sible either by the bracket c remaining vertical, while yoke a undergoes linear and angular displacement, or by yoke a remaining static while bracket c rotates about 1 or by a combination of both of those actions.

The pin e could be replaced by any latch, snib or other catch, and such catch could be operated by an electrical solenoid or by hydraulic means or by any other means, preferably so as to enable an operator on the ground or in the crane cab or at some other station to convert the hook suspension from a free swing to a non-swing suspension when required.

Should indefinite linear swing of the hook d be desirable, the yoke a may be replaced by a pulley a as in FIG. 3. Here the rope b is continuous round a pulley a rotatably mounted on a pin f journalled in the hook bracket c A suitable brake shoe h is attached to an operating ram j mounted on the hook bracket 0 This brake shoe is arranged releasably to clamp the rope b and pulley a together, thus preventing movement of the rope with regard to the bracket 0 On applying the brake shoe the resulting suspension corresponds to that of FIG. 2 with the pin e of the latter inserted, i.e., the hook centre cannot be displaced in the direction AA without one rope becoming slack. On releasing the brake shoe no constraint is offered to an increase in the length of one half of the rope and a corresponding decrease in the length of the other half; consequently the hook becomes free to swing linearly through an unlimited arc.

3 The brake could be operated or controlled by a handoperatcd screw, a spring with hand-operated release or any other mechanism for achieving the same object, ineluding remote or power-operated swing locking devices.

FIG. illustrates a form the means of the invention mounted local to the winding gear. The winding gear illustrated in FIGURE 4- is a typical winding gearthat can be used in all of the other tbodiments shown in the other figures. Reference k is the crane crab; l is the rope drum; in are pulleys mounted in a rocking frame it pivoted about a pin p, and its angle of rock limited by adiustable stops g. When the stops g are caused to bear equally on the two sides of the proiection r of the rocking frame 12, the condition as in PEG. 1 is obtained, while retraction of the stops g (to the position shown) allows freedom of linear swing of the hook a. The stops g may be simple screwed spigots locked by locknuts to give a predetermined limited swing, or may be power operated jacks, hydraulic rams or other means whereby an operator may adg'ust the limit of the linear swing from a remote station.

it variable adjustment of swing limit is not desired, a catch can be incorporated to either lock the rocking frame is to the crab k or else free it to rotate without limit. Such a catch could be manually, power or remote power operated.

Hook suspensions in accordance with the invention may be ppl ed in two planes so as to give dilierent linear swing limitations at will in two orthogonal directions. Thus, for example, beam cranes could have the linear swing completely locked in the direction along the beam and be free to swing the beam at right angles to itself.

A four rope suspension embodying the invention is shown in PEG. 5, which is a duplicate of the P16. 2 arrangement, t e hook suspension assemblies bein at right angles to one another. Bracket c, to which yoke a is pivoted at f, is itself pivoted at h to a second yoke Ropes b and 5 are connected to the yokes a and (1 as shown. Swing inhibiting pins e e arefitted to the yokes.

With both pins e and 2 inserted linear hook swing is completely prevented. Removal of the pin 6 permits free swing parallel to AA only; removal of pin 2 permits free swing parallel to BB only; removal of both pins allows iree swing in all directions.

Kinematically the trajectories allowed by the various ropes are not identical. Consider the case where the pins 2 are both removed, and the hook d is swinging parallel to AA. The ropes [2 12 tend to constrain the hook to swing in a circular arc, whereas the ropes b b tend to constrain the hook to swing in approximately an elliptical arc with the pulley cent-res g g as loci. In general the discrepancy between these arcs for small oscillations is negligible, but they can result in one or other of the rope pairs becoming slack. However, the incorporation of spring shackles t t and t t with high rate, small deflection, springs preferably arranged in compression Will obviate this undesirable feature.

For constraining swing in both horizontal directions a three rope hook suspension is the most economical, and FIG. 6 and 7 show the application of the previously described principle to such a suspension. FIG. 6 shows a linkage for attachment to a hook. This comprises three units each similar to that used in FIG. 2 viz. three yokes a pivoted on pivots f to three brackets 0 upstanding from a triangular plate m, each bracket being equipped with a removable pin 6 The adjacent yokes a are connected by links it having slidable ball jointed ends. The three ropes b are attached to the centres of each of the three links n. It will be apparent that when the three pins a are inserted swing is prevented, while removal of 4 the pins allows a fully balanced flexible linkage permitting linear swing in all directions.

Corresponding to 4, a three pulley assembly for crab mounting is shown schematically in FIG. 7. Three cylinders are connected by piping to a central valve w. l-iydraulic are connected to rods x each carrying a bracket and pulley wheel 2. For simplicity only one of the three pulleys is shown but it will be understood that ropes passed about these pulleys are connected to the winding gear and to the crane hook bracket, The central valve w is such as to either connect all three hydraulic cylinders together or to plug the junction and isolate each of the three cylinders. in operation, if valve w be closed the three pulleys and mountings become rigidly constrained vertically and the three hoisting ropes which converge at the hook constrain the load and prevent linear swing.

it" the valve w be opened, the pulleys become free to move vertically except that as one is lowered the others must rise such that the sum total of the vertical movements is zero. The pulleys may thus rise and fall to allow swinging of the book.

i claim:

1. in combination, a crane with a rope winding gear, a hook suspension member, a load lifting hook secured to said suspension member, a first hinge pin 'pivotally mounting a first yoke member on said suspension memer, said first yoke adapted to pivotally swing in one vertical plane, a removable first pin member extending through said suspension member and said first yoke menier to prevent said first yoke member from pivotally swinging in said one vertical plane, a first pulley guided rope suspension connected to said first yoke member on opposite sides of said hinge pin and to said winding gear.

2. combination, a crane with a rope winding gear, a hook suspension member, a load lifting hook secured to said suspension member, a first hinge pin pivotally mounting a first yoke member on said suspension member, said first yoke member adapted to pivotally swing in one vertical plane, a removable first pin member extending through said suspension member and said first yoke member to prevent said first yoke member from pivotally swinging in said one vertical plane, a first pulley guided rope suspension connected to said first yoke member on opposite sides of said hinge and to said winding gear, a second hinge pin member pivotally mounting a second yoke memher to said suspension member at right angles to said first yoke member, said second yoke member adapted to pivotally swing in a second vertical plane, a removable second pin member extending through said suspension member and said second yoke member to prevent said second yoke member from pivotally swinging in said second vertical plane, a second pulley guided rope suspension connected to opposite sides of said second hinge pin and to said winding gear, whereby linear swing of said book can be precisely controlled in both of said two vertical planes.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN COMBINATION, A CRANE WITH A ROPE WINDING GEAR, A HOOK SUSPENSION MEMBER, A LOAD LIFTING HOOK SECURED TO SAID SUSPENSION MEMBER, A FIRST HINGE PIN PIVOTALLY MOUNTING A FIRST YOKE MEMBER ON SAID SUSPENSION MEMBER, SAID FIRST YOKE ADAPTED TO PIVOTALLY SWING IN ONE VERTICAL PLANE, A REMOVABLE FIRST PIN MEMBER EXTENDING THROUGH SAID SUSPENSION MEMBER AND SAID FIRST YOKE MEMBER TO PREVENT SAID FIRST YOKE MEMBER FROM PIVOTALLY SWINGING IN SAID ONE VERTICAL PLANE, A FIRST PULLEY GUIDED ROPE SUSPENSION CONNECTED TO SAID FIRST YOKE MEMBER ON OPPOSITE SIDES OF SAID HINGE PIN AND TO SAID WINDING GEAR. 